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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 15 |
| 4 | 81 |
| 5 | 462 |
| 6 | 2718 |
| 7 | 16344 |
| 8 | 99900 |
| 9 | 618567 |
| 10 | 3870909 |
| 11 | 24441021 |
| 12 | 155510523 |
| 13 | 996109245 |
| 14 | 6418243575 |
| 15 | 41572149615 |
| 16 | 270536350545 |
| 17 | 1767990955980 |
| 18 | 11598120859860 |
| 19 | 76347126498420 |
| 20 | 504148079084940 |
| 21 | 3338585176489560 |
| 22 | 22166530404950520 |
| 23 | 147525638070221640 |
| 24 | 983978335278966456 |
| 25 | 6576191509703182677 |
| 26 | 44031626057441376423 |
[1,3,15,81,462,2718,16344,99900,618567,3870909, 24441021,155510523,996109245,6418243575, 41572149615,270536350545,1767990955980, 11598120859860,76347126498420,504148079084940, 3338585176489560,22166530404950520, 147525638070221640,983978335278966456, 6576191509703182677,44031626057441376423] |